The U.S. Navy will divert an amphibious assault ship that has been providing hurricane relief on the Caribbean island of Dominica to assist in Puerto Rico, the latest piece in an expanding Defense Department mission to provide assistance there, U.S. military officials said Friday.

The USS Wasp will respond with a few hundred additional sailors and Marines and their equipment, most notably helicopters. The 843-foot ship initially deployed from its home port in Norfolk, on Aug. 30 on its way to Japan, but has been providing hurricane relief for weeks, following both hurricanes Irma and Maria. It has dozens of hospital beds aboard.

Three military officials, speaking on the condition of anonymity in order to discuss ongoing operations, said that the Wasp’s mission in Dominica is now considered complete, and the ship will shift to assisting in Puerto Rico sometime this weekend. U.S. Northern Command disclosed the move in a list of hurricane-relief operations Friday morning.

The deployment of the Wasp to Puerto Rico comes as senior U.S. officials defend against growing criticism that their response to Maria is too slow. The Defense Department stepped up its response significantly Tuesday, and has defended its actions while saying that they have provided everything that the Federal Emergency Management Agency and the Puerto Rico government has asked for quickly.

The Wasp was the first Navy ship to respond in the U.S. Virgin Islands after Hurricane Irma, arriving Sept. 7 and responding in locations that included St. Thomas, St. John and St. Croix. It and two other Navy combat ships, the USS Kearsarge and USS Oak Hill, stayed in the region for days, and then moved south Sept. 18 to avoid the path of Hurricane Maria.

After Maria passed, senior U.S. commanders sent the Wasp to respond in the Leeward Islands, a chain of islands southeast of Puerto Rico that includes the U.S. Virgin Islands. Meanwhile, the Kearsarge — which also is equipped with dozens of hospital beds — and Oak Hill deployed to Puerto Rico, providing initial disaster relief.

Sailors flying off the Wasp in MH-60 Seahawk helicopters have evacuated people from Dominica in recent days, and rescued two civilians who crashed off the coast of Dominica in a Cessna aircraft Thursday, U.S. military officials said. Photographs released by the Navy show some of the evacuees coping with injuries, and there are numerous children among them.

U.S. officials have said that they expect the relief in Puerto Rico to shift from primarily being a naval effort led by the USS Kearsarge and USS Oak Hill to being a land-based mission overseen by two senior Army officers who arrived there this week: Lt. Gen. Jeffrey Buchanan and Brig. Gen. Richard Kim. About 4,400 U.S. troops are now a part of the federal response on the island.

But the naval effort will continue to grow anyway. In addition to the Wasp joining the mission, the USNS Comfort, a hospital ship, is expected to deploy Friday from Norfolk, and arrive off the coast of Puerto Rico early next week. The ship began preparing to deploy last week, but U.S. officials decided last weekend against sending it, said Thomas LaCrosse, the Pentagon’s director of defense support to civil authorities.

However, on Tuesday, Federal Emergency Management Agency Director William “Brock” Long announced at the White House that the Comfort would be deploying after all. That decision came amid growing criticism that it should already have been at sea heading toward the island.